1. Field of the Invention:
The present invention relates to coupled cavity circuits that may be utilized in microwave electron tubes such as traveling-wave tubes or klystrons and, more particularly, to an iris configuration utilized within coupled cavity circuits that increases the resonant frequency of the iris.
2. Discussion of the Prior Art:
Microwave electron tubes such as traveling-waves tubes or klystrons are well known in the art. These devices may be designed to operate at ultra-high frequencies or microwave frequencies within a desired bandwidth of such frequencies. The design of the microwave tube to provide the desired bandwidth of frequencies is often based upon a series of cavities through which an electron beam must travel. The electric waves created in the cavities by an electron beam or the external excitation by a low-power radio frequency source act upon the electrons in the beam and cause them to change speed so they arrive at a subsequent cavity in increasingly dense bunches. At the output of the tube, the energy of the electrons is absorbed by the field of an output device to contribute to the function of that device.
A klystron tube, such as an extended interaction klystron, may use two or more cavities coupled by openings or irises between the cavities. Similarly, a traveling-wave tube, such as a coupled-cavity, traveling-wave tube, may use from five to thirty cavities with coupling irises.
A paper describing an extended interaction klystron was written by T. Wessel-Berg, "A General Theory Of Klystrons With Arbitrary, Extended Interaction Fields," Microwave Lab., Stanford University, Stanford, California, Tech. Rept. No. 376; March, 1957. A second paper on the subject was written by M. Chodorow, "A High-Frequency Klystron With Distributed Interaction," The Transactions Of Electron Devices, p. 44, Jan., 1961.
It is desirable to design a microwave electron tube, such as a coupled-cavity, traveling-wave tube or an extended interaction klystron, with as broad a bandwidth of frequency responses as possible.